17alpha-hydroxy-19-norprogesterone, process therefor and intermediates obtained thereby



17a-HYDROXY-lQ-NORPROGESTERONE, PROCESS THEREFQR AND INTERMEDIATES OBTAINED THEREBY Carl Djerassi, Birmingham, Mich., and Franz Sondheimer and George Rosenkranz, Mexico City, Mexico, as signors to Syntex, S. A., Mexico City, Mexico, a corporation of Mexico No Drawing. Application April 23, 1954, Serial No. 425,310

Claims priority, application Mexico April 25, 1953 8 Claims. (Cl. 260397.4)

The present invention relates to the production of novel cyclopentanophenanthrene derivatives and to a novel process for the production thereof.

More particularly the present invention relates to the production of the novel active cortical hormone 19-nor- 17oz hydroxyprogesterone (A l9 nor pregnen 17m 01 3,20 dione) and to the production of novel intermediates convertible thereto. As pointed out in application Serial Number 425,300 filed as of even date herewith 19-nor-17u-hydroxyprogesterone is also useful as an intermediate for the production of the active cortical hormone A l9 nor pregnen 113, 170:, 21 triol- 3,20-dione by incubation with adrenal tissue.

In accordance with the present invention it has been discovered that a novel intermediate, i. e. the ZO-ketal of 3 methoiiy 17a hydroxy 17B acetyl 1,3,5(10)- estratriene upon reduction with lithium metal or other alkali metal in liquid ammonia gives a second novel intermediate, i. e. the 20-ketal of 3-methoxy-l7 -hydrxy-A -19-nor-pregnadien-20-one which may then be converted to the novel cortical hormone 19-nor-17ahydroxyprogesterone.

It has further been discovered in accordance with the present invention that the intermediate ZO-ketal 'of 3- methoxy 17cc hydroxy 17,6 acetyl 1,3,5 4 estratriene may be prepared by novel methods from the known compounds 3 hydroxy 17B acetyl 1,3,5(10), 16- estratetraene and 3,17fi-dihydroxy-17-acetyl-l,3,5 (10)- estratriene disclosed in the publication of Djerassi et al., J. A. C. S. 73, 1526 (1951).

A portion of the process of the present invention is set forth in the following equation wherein lithium metal ice is used as the reducing agent by way of illustration although other alkali metals may also be used:

l Acid om M o Lithium Metal Liquid Ammonia In practicing the steps above set forth the 20-ketal of 3 methoxy 17a hydroxy 17 3 acetyl 1,3,5(10)- estratriene was dissolved in an organic solvent such as anhydrous ether and added dropwise to lithium metal dissolved in liquid ammonia. After a short time methanol was added and the ammonia .was then allowed to evaporate overnight at room temperature. After purification as hereinafter set forth the 20 ketal of 3-rnethoxya -hydroxy 17B acetyl A estradiene was obtained. Hydrolysis and rearrangement of this ketal with an acid such as hydrochloric acid produced A 119- nor-pregnen-l7a-ol-3,20-dione (19-nor-117a-hydroxypro gesterone). V

The ZO-ketal of B-methoxy-l7a-hydroxy-17B-acetyl 1,3,5 (10)-estratriene may bev prepared from either 3 -hy.- droxy-17B-acetyl-1,3,5 (10),16-estr atetraene or 3,17oz -djlf hydroxy-17-acety1-1,3,5 (lO)-estratriene as outlined in the following equation:

the reaction with the glycol to form the ketal (II to VIII) is performed prior to the reaction with methyl sulfate and IJHs IJHs CH3 C O O O O I H l l j ,0 ,0 Alkaline Methyl H202 HO Sulfate Athylene /Hl3r r! Glycol TE:

C/ 1 CH3 \O VIII VI 0H Ethylene F l Glycol HO- CHiO- Lithium Catal tic I Aluminum y i'Hydride l Reduction THa ('JHa O O C CH3 C 1 I O IX pl vIr j IV I HO- (meow n; i

Methyl V Ethylene Lithium Ethylene Sulfate Glycol Aluminum Hydride 0 I 1 CO l o :---OH I :--OH

HO CH O- As may be noted byreferring to the foregoing equation inthe second path the 160:, l7oc-0Xid0 group of compound III is converted to the corresponding brornohydrin with HBr to form compound VI, the bromine is then removed by catalytic reduction to form compound VII and Y then this last compound is reacted with ethylene glycol for irampl e to form compound V. The last of the three pathsienumerated is entirely similar to the first path exept that the order of the' various steps is changed. Thus,

the reduction of the oxido group with lithium aluminum hydride also precedes the reaction with methyl sulfate.

In addition to the above discussed procedures for the preparation of the compound indicated as V, it may be noted that by starting from 3,17a-dihydroxy-17-acetyll,3,5( l0)-estratriene (X) which is already provided with a l7a-hydroxy group certain steps may be eliminated and only the reaction with the glycol (X to IX) followed by reaction with methyl sulfate (IX to V) is necessary.

It may be noted further that the conditions involved in each of the similar steps above outlined are the same in all essential respects, For the reaction of t3fl-hydroxyl7B-acetyl-l,3,5(l0),.l-estratetraene (I) with hydrogen peroxide the steroid is dissolved in an organic solvent such as methanol, the solution cooled and hydrogen per oxide as well as aqueous alkali such as sodium hydroxide added separately and slowly thereto. The reaction mixture was'allowed to stand in the cold for a short time and then overnight at room temperature. After purificasuch as 16a,L 7e-oxido-3-methoxy-17,8-acetyl-l,3,5(10)- estratriene (IIIIor l6a,17ol-oxido-3B-hydroxy-17fi-acetyl- 1,3,S(.10)-estratriene (II) or 3-methoxy-17a-hydroxy-17flacetyl-1,3,5()-estratriene (VII) or 3,l7a-dihydroxy-17flacetyl-1,3,5(10)-estratriene (X) was dissolved in an organic'solvent, such as benzene, containing ethylene glycol and a catalytic amount of a strong organic acid such as p-toluenesulfonic acid and refluxed for a prolonged period such as ten hours. Purification gave the corresponding compounds IV, VIII, V and IX respectively.

The l6ot,l7zx-0Xid0 group as may be noted from the equation can be converted to a 17u-hydroxy group by reduction with lithium aluminum hydride (compound IV to V and compound VIII to IX) or by adding I-IBr followed by catalytic reduction to remove the l7-bromo group of the bromohydrin (compound III to VI to VII). For the reaction with lithium aluminum hydride the starting steroid the ZO-ketal of 16e,17e-oxido-3-methoxy-17l8- acetyl-1,3,5(10)-estratriene (IV) or the ZO-ketal of 16a,- 17a oxido 3/3-hydroxy-17/3-acetyl-1,3,5(10)-estratriene (VIII) is dissolved in an anhydrous organic solvent such as tetrahydrofurane and refluxed with lithium hydride which is added in an organic solvent such as ether. The excess hydride is decomposed, and the products (V or IX) precipitated and purified.

For the reaction of 16a,17a-oxido-3-methoxy-17B- acetyl-l,3,5(10)-estratriene (III) with I-IBr the compound is dissolved in acetic acid and a solution of hydrobromic acid in acetic acid added thereto while the temperature is maintained just below room temperature. The solution is then allowed to stand for a short time at room temperature and is then poured into cold water to precipitate the bromohydrin i. e. l6-bromo-3-methoxy-17ahydroxy-17fi-acetyl-l,3,5 (10) estratriene (VI). The bromohydrin is then treated with hydrogen in the presence of a hydrogenation catalyst, preferably a palladium catlyst until 1 mol of hydrogen is absorbed. Upon purification the compound VII is produced.

The following specific examples serve to illustrate but are not intended to limit the present invention:

Example I To a solution of 3 g. of 3-hydroxy-l7-acetyl-l,3,5 (10),- l6-estratetraene (I) in 100 cc. of methanol, cooled in an ice bath, was added dropwise and simultaneously from two separatory funnels 6 cc. of 30% hydrogen peroxide and a solution of 4 g. of sodium hydroxide in cc. of water. The two solutions were added in a period of approximately 15 minutes. The mixture was kept for 30 minutes in the cold and then overnight at room temperature. After diluting with water and acidifying the product was extracted with chloroform and the chloroform solution was dried over sodium sulphate and evaporated to dryness. Recrystallization from chloroform-methanol yielded 3 g. of the 16,17-epoxide (II) with a melting point of 234236 C.; [el +124 (chloroform).

Example I] A boiling solution of 2.5 g. of the l6,l7-epoxide (II), obtained in accordance with Example I, in 180 cc. of methanol was alternatively treated with four portions of 7 cc. of 50% potassium hydroxide and 7 cc. of methyl sulfate. After ten minutes, the solution was cooled, di-

luted with water and the precipitate was collected and well washed with water. Crystallization from acetonehexane afforded 2.5 g. of the methylether (III) with melting point 142-145 C.; [061D (chloroform).

Example III A solution of 3 g. of the methyl ether (III), obtained in accordance with the previous example, in 60 cc. of benzene containing 6 cc. of ethylene glycol and a trace of p-toluenesulfonic acid, was refluxed for ten hours using an adapter for the removal of the water formed in the course of the reaction. Dilute potassium hydroxide solution was added and the benzene layer was repeatedly washed with water, dried and evaporated to dryness. Recrystallization from acetone-hexane gave the ZO-ketal (IV).

Example IV 0.3 g. of lithium aluminum hydride in 10 cc. of anhydrous ether was added toa solution of 3 g. of the ketal, obtained in accordance with the previous example, in 50 cc. of tetrahydrofurane. The solution was refluxed for one hour and the excess of hydride was decomposed by the addition of ethyl acetate. Then a saturated solution of sodium sulfate was added, followed by 3 g. of solid sodium sulfate. The precipitate was filtered and washed with ether and the combined filtrates were evaporated to dryness. Crystallization from acetone-pentane afforded the 20-ketal of 3-methoxy-l7a-hydroxy-17,8-acetyl-l,3,5- (10)-estratriene (V) with melting point l24l26 C.: [041 +44 (chloroform).

Example V 3 g. of the 16,17-epoxide (II) obtained in accordance with Example I, was treated with ethylene glycol by the procedure described in Example III. The resulting ketal (VIII) was treated with lithium aluminum hydride by the procedure described in Example IV, to give the 20- ketal of 3,l7a-dihydroxy-17fi-acetyl-1,3,5(10)-estratriene (IX), which on treatment with methyl sulfate, by the procedure'described in Example II, produced the 20-ketal of 3- methoxy 17ot-hydroxy-17fi-acetyl-1,3,5(10)-estratriene (V) identical to the one obtained in accordance with Example IV.

Example VI 3 g. of 3,l7e-dihydroxy-17/3-acetyl-l,3,5(l0)-estratriene (X) was treated with ethylene glycol, by the procedure described in Example III to give 1.7 g. of the-ZO-ketal (IX), identical to the one obtained in accordance with Example V.

Example VII To a solution of 1 g. of 3-methoxy-l6a,17a-oxidel7/8acetyl-l,3,5(10)-estrat1iene (III) prepared according to Example II, in 10 cc. of acetic acid, there were added 2 cc. of a 32% hydrobromic acid solution in acetic acid while maintaining the temperature constant between 15 and 18 C. The solution was allowed to stand for 15 minutes at room temperature and is emptied into 15 times its volume of iced water with agitation in order to obtain a uniform precipitation. The precipitate was filtered, washed to neutrality and dried atroom temperature. The yield of bromohydrin (VI) was almost quantit-ative.

1 g. of the bromohydrin thus obtained was agitated in an atmosphere of hydrogen at atmospheric pressure with 3 g. of 2% previously reduced palladium hydroxide upon calcium carbonate and 20 cc. of ethanol previously distilled over Raney nickel. In the course of two hours there was absorbed the equivalent of one mol of hydrogen. The precipitate was filtered and washed with water. The dry product was crystallized from acetone-hexane. 0.8 g. of 3-methoxy-l7ol-hydroxy-l7B-acetyl-l,3,5(l0)- estratriene (VII) with a melting point of 1SO-152 C. [m1 4S (chloroform) was obtained.

Example VIII Example IX 1.4 g. of lithium metal (wire) was dissolved in 150 cc. of liquid ammonia in a Dewar flask fitted with a mechanical stirrer, and then a solution of 1.4 g. of the ZO-ketal of '3 methoxy 17oz. hydroxy 17,8 "acetyl 1,3,5()- estratriene, in 150 cc. of anhydrous ether was added dropwise in the course of approximately five minutes. After ten minutes longer, 16 cc. of absolute methanol was added dropwise in the course of 20 minutes. The ammonia was allowed to evaporate overnight at room temperature and the residue was collected with cold water and extracted with ethyl ether. The ether extract was washed to neutral, dried and evaporated to dryness. Recrystallization from acetone-hexane yielded 1.0 g. of the ZO-ketal of 3-meth0xy-17a-hydroxy-17;3-acetyl-A estradiene melting point 175 -176 C. (Kofler); [al +74 (chloroform).

Example X p 30 cc. of a 3 N solution of hydrochloric acid was added-to a solution of 1 g. of the 20-ketal of 3-methoxy- 17a-hydroxy-19-nor-A -pregnadien-20-one in 50 cc. of methanol and the mixture was heated at a temperature of 60 C. for minutes. The cooled mixture was mixed with water and ether and therether layer was washed with sodium bicarbonate solution and water until neutral, dried over sodium sulfate and evaporated to dryness. Upon crystallization from acetone A -l9-nor-pregnen- 17a-Ol-3,20-Cli0n6 is obtained having a melting point of 204-206 C.; [111 +41 (chloroform) which showed the typical ultraviolet absorption maximum at 240 m (log E 4.20).

We claim:

1. A process for the production of 19-nor-17u-hydroxyprogesterone which comp-rises reducing the -ketal of 3 methoxy 17a hydroxy 17,8 acetyl l,3,5(l0)- es-t'ratriene with an alkali metal in liquid ammonia to form the 20-ketal of 3-II'1Etl1DXY-17Ct-hYd1'OXY-A 19-nor-pregnadien-20-one and thereafter hydrolysing and rearranging the last mentioned ketal in an acid medium.

2. The process of claim -1 wherein the alkali metal is lithium.

3. .A process for the production of l9-nor-l7oz-hydroxyprogesterone which comprises treating 3-hydroxy-17pacetyl-1,3,5(10), 16-estratetraene with hydrogen peroxide in alkaline medium to form 16c ,17 x-oxido-3-hydroxyl7(3acetyl-1,3,5(10)-estratriene, thereafter forming from the oxid o compound the ZO-ketal of 3-methoXy-17a;hydroxy-17fl-acetyl-1,3,5(10)-estratriene by treating the oxido compound in indiiferent order with a methylating agent to form the 3-methoxy group and a ketalizingagent to form the ZO-ketal group followed by reduction to con vert the oxido group into a 17OL-hYdl'OXy group, reducing the ZO-ketal compound with an alkali metal in liquid ammonia to form the 20-ketal of 3-methoxy-17a-hydroxy- A -19-nor-pregnadien-2O-one and thereafter hydroly'sing and rearranging the last mentioned ketal in an acid medium.

4. The process of claim 3 wherein the methyla-ting agent is methyl sulfate, the ketalizing agent is ethylene glycol in the presence of p-toluenesulfonic acid, the re ducing agent is lithium aluminum hydride and the alkali metal is lithium.

5. A process for the production of 19-nor-17u-hy- 1 droxyprogesterone which comprises treating 3-hydroxyl7,8-acetyl-1,3,5(10), 16-estratetraene with hydrogen peroxide in alkaline medium to form l6ez,-7oi-oxido-3- hydroxy-17fl-acetyl-1,3,5 ('10)-estratriene, thereafter forming from the oxido compound the ZO-ketal of 3-methoxy 17u-hydroxy-l7fl-acetyl-1,3,5(10)-estratriene by treating the oxide compound with a methylating agent and then with hydrobromic acid to form 16-bromo-3-methoxy- 17a-hydroxy-17fi-acetyl-1,3,5 10)-estratriene, treating the 16-bromo compound with hydrogen in the presence of a hydrogenation catalyst to remove the 16-bromo group and form' 3 methoxy 17a hydroxy 17,8 acetyl- 1,3,5(10)-estratriene and treating this last mentioned compound with a ketalizing agent, reducing the 20-ketal compoundwith an alkali metal in liquid ammonia to form the ZO-ketal of 3-methoxy 17a-hydroxy A -19-norpregnadien-ZO-one andthereafter hydrolysing and rear ranging the last mentioned ketal in an acid medium.

6. The process of claim 5 wherein the methylating agent is methyl sulfate, the ketalizing agent is ethylene glycol in the presence of p-toluenesulfonic acid and the alkali metal is lithium.

7. 16 bromo 3 methoxy 17a hydroxy 17,8- acetyl-1,3 ,5 10) -estrat-riene.

8. A -19-nor-pregnene-17a-ol-3,20-dione.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PROCESS FOR THE PRODUCTION OF 19-NOR-17A-HYDROXYPROGESTERONE WHICH COMPRISES REDUCING THE 20-KETAL OF 3-METHOXY-17A-HYDROXY-17B-ACETYL-1,3,5(10)ESTRATRIENE WITH AN ALKALI METAL IN LIQUID AMMONIA TO FORM THE 20-KETAL OF 3-METHOXY-17A-HYDROXY-$2,5(10)19-NOR-PREGNADIEN-20-ONE AND THEREAFTER HYDROLYSING AND REARRANGING THE LAST MENTIONED KETAL IN AN ACID MEDIUM. 